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#include "php_snuffleupagus.h"
#include "ext/standard/url.h"
ZEND_DECLARE_MODULE_GLOBALS(snuffleupagus)
static zend_long nonce_d = 0;
static void generate_key(unsigned char *key) {
PHP_SHA256_CTX ctx;
const char *user_agent = getenv("HTTP_USER_AGENT");
const char *env_var =
getenv(SNUFFLEUPAGUS_G(config).config_snuffleupagus->cookies_env_var);
const char *encryption_key =
SNUFFLEUPAGUS_G(config).config_snuffleupagus->encryption_key;
assert(32 == crypto_secretbox_KEYBYTES); // 32 is the size of a SHA256.
assert(encryption_key); // Encryption key can't be NULL
PHP_SHA256Init(&ctx);
if (user_agent) {
PHP_SHA256Update(&ctx, (unsigned char *)user_agent, strlen(user_agent));
}
if (env_var) {
PHP_SHA256Update(&ctx, (unsigned char *)env_var, strlen(env_var));
} else {
sp_log_err("cookie_encryption",
"The environment variable '%s'"
"is empty, cookies are weakly encrypted.",
SNUFFLEUPAGUS_G(config).config_snuffleupagus->cookies_env_var);
}
if (encryption_key) {
PHP_SHA256Update(&ctx, (const unsigned char *)encryption_key,
strlen(encryption_key));
}
PHP_SHA256Final((unsigned char *)key, &ctx);
}
// This function return 0 upon success , non-zero otherwise
int decrypt_zval(zval *pDest, bool simulation, zend_hash_key *hash_key) {
unsigned char key[crypto_secretbox_KEYBYTES] = {0};
unsigned char *decrypted;
zend_string *debase64;
int ret = 0;
debase64 = php_base64_decode((unsigned char *)(Z_STRVAL_P(pDest)),
Z_STRLEN_P(pDest));
if (ZSTR_LEN(debase64) <
crypto_secretbox_NONCEBYTES + crypto_secretbox_ZEROBYTES) {
if (true == simulation) {
sp_log_msg(
"cookie_encryption", SP_LOG_SIMULATION,
"Buffer underflow tentative detected in cookie encryption handling "
"for %s. Using the cookie 'as it' instead of decrypting it.",
ZSTR_VAL(hash_key->key));
return ZEND_HASH_APPLY_KEEP;
} else {
sp_log_msg(
"cookie_encryption", SP_LOG_DROP,
"Buffer underflow tentative detected in cookie encryption handling.");
return ZEND_HASH_APPLY_REMOVE;
}
}
generate_key(key);
decrypted = ecalloc(ZSTR_LEN(debase64), 1);
ret = crypto_secretbox_open(
decrypted,
(unsigned char *)(ZSTR_VAL(debase64) + crypto_secretbox_NONCEBYTES),
ZSTR_LEN(debase64) - crypto_secretbox_NONCEBYTES,
(unsigned char *)ZSTR_VAL(debase64), key);
if (-1 == ret) {
if (true == simulation) {
sp_log_msg(
"cookie_encryption", SP_LOG_SIMULATION,
"Something went wrong with the decryption of %s. Using the cookie "
"'as it' instead of decrypting it",
ZSTR_VAL(hash_key->key));
return ZEND_HASH_APPLY_KEEP;
} else {
sp_log_msg("cookie_encryption", SP_LOG_DROP,
"Something went wrong with the decryption of %s.",
ZSTR_VAL(hash_key->key));
return ZEND_HASH_APPLY_REMOVE;
}
}
ZVAL_STRINGL(pDest, (char *)(decrypted + crypto_secretbox_ZEROBYTES),
ZSTR_LEN(debase64) - crypto_secretbox_NONCEBYTES - 1 -
crypto_secretbox_ZEROBYTES);
return ZEND_HASH_APPLY_KEEP;
}
zend_string *encrypt_zval(char *data, unsigned long long data_len) {
const size_t encrypted_msg_len = crypto_secretbox_ZEROBYTES + data_len + 1;
const size_t emsg_and_nonce_len =
encrypted_msg_len + crypto_secretbox_NONCEBYTES;
unsigned char key[crypto_secretbox_KEYBYTES] = {0};
unsigned char nonce[crypto_secretbox_NONCEBYTES] = {0};
unsigned char *data_to_encrypt = ecalloc(encrypted_msg_len, 1);
unsigned char *encrypted_data = ecalloc(emsg_and_nonce_len, 1);
generate_key(key);
/* tweetnacl's API requires the message to be padded with
crypto_secretbox_ZEROBYTES zeroes. */
memcpy(data_to_encrypt + crypto_secretbox_ZEROBYTES, data, data_len);
assert(sizeof(zend_long) <= crypto_secretbox_NONCEBYTES);
if (0 == nonce_d) {
/* A zend_long should be enough to avoid collisions */
if (php_random_int_throw(0, ZEND_LONG_MAX, &nonce_d) == FAILURE) {
return NULL; // LCOV_EXCL_LINE
}
}
nonce_d++;
sscanf((char *)nonce, "%ld", &nonce_d);
memcpy(encrypted_data, nonce, crypto_secretbox_NONCEBYTES);
crypto_secretbox(encrypted_data + crypto_secretbox_NONCEBYTES,
data_to_encrypt, encrypted_msg_len, nonce, key);
zend_string *z = php_base64_encode(encrypted_data, emsg_and_nonce_len);
return z;
}
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